Pneumatic tool.



l No. '726,074. PATENTED APR. 21, 190s.

.-H. G. ROTTEN. PNEUMATIG TOOL.

Y APLIOATION FILED JULY 17. 1901. I0 MODEL.

,UNITED STATES PATENT OFFICE.

HERMAN G. KOTTEN, OF NEW YORK, N. Y.

PN EU ,IVIATilC TOOL.

SPECIFICATION forming part of Letters Patent No. 726,074, dated April 21, 1903.

' A1p1ican0nii1eaqu1y 17,'1QQ1. senai No. 58,593. (No model.)

To iLZZ when@ #may concern.; f

Beit known 'that I, HERMAN G.' Ko'rrEN, a citizen ofthe United States, residing in the city, county, and State offNew York, have invented a new and use fnl Improvement Pneumatic Tools, of which the following is a specification.

My invention consists, broadly, of a valveless pneumatic tool having a differential-diameter piston, whereinvmeans are provided for permitting the pressure to exhaust from the small pressure area of the piston when the latter has made its extreme backward stroke, whereby there Will be no cushion on said piston when it delivers its forward blow upon the shank of the chisel or other tool employed.

My invention also consists of the novel arrangement and location of the inletand exhaust ports and passages common to the cylinder and piston of ,the tool, Wherebysaid piston is reciprocated and the exhaust there? from permitted at the proper intervals, so that the pistonis' caused tovstrileafulland unobstructed blow upon the ychisel at its forward stroke.' l. g It also consists' in lproviding a plurality of inlet ports andpassage's forfthe'motive iiuid and arranging'oneof the latter sol thatit will be only part-lyopen when the othersare closed; so as to permit theentrance of but a small portion of the motive fluid to effect the return` of the piston.

It also consists of a novel construction of a differential piston.

Itifnrther consists of novel details of construction, all aswill be hereinafter more fully described, and pointed out in the claims,

Figures 1 and 2 represent longitudinal sectional views of a valveless pneumatic tool embodying my invention, showing the piston thereof in its different or extreme positions.

Similar numerals of reference indicate corresponding partsin the figures.

Referring to the drawings, 1 designates a pneumatic "tool consistingv of thecylinder 2,

` having v the rinlet-piecev `3 andthe. nose-piece or bushing 4, in which latter is received the shank`5 of the working tool 6.

7 designates the main inlet-port, which communicates with the passages 8, 9, and 10,which discharge into the main inlet-ports 11, 12, and

l,and 13.

13, respectively, it beinghoted that the inletportll is somewhat lower than the ports 12 diameter and are joined by the reduced portion, groove, or neck 17 and the enlarged head 18, which is of greater diameter than said heads l5 and 16, said head 18 being joined to the head 16 bythe neck or groove 19,while the' opposite extremity ot the piston is provided with the striker 20.

It will be seen that the groove l7 forms a chamber between the piston and cylinder, thereby permitting the live air or other motive iinid to enter the port 2l when the port-s are in the position seen in Fig. 1, said air flowing through the passage 22 and rentering the cylinder through the port 23, thereupon actvving ,upon the shoulder 24 and moving the piston lt toward the' inletpiece 3 or from the position seen in Fig..1 into the position seen in Fig. 2.

Referring now to Fig. it willbe seen that the eXhaust-port25 isopenerd, when the parts are inthe position seen therein, whereupon aircan. exhaust throughvthe passage 26 and vport l27.1to the atmosphere.

Reference being still had to Fig. 2, it will be seen that the inlet-port 28 being now open through the medium of the groove 17 at the same time when the exhaust-port 25 is opened live air is permit-ted to enter said port 28 and passes through the passage 29 and port 30 into the chamber 31 and presses upon the large area 32 of the piston, thereby driving the latter toward the toolY 6 till the striker 2O impacts against the shank 5 thereof.

When the parts are in the position seen in Fig. 1, the exhaust-port 33 is open, thereby permitting the air to vpass therethrough to the passage 26 and exhaustport 27, while the accumulating air on the front endof 4the piston will passithrough the Aexhaust-port 34 and passage ,5.92m the atmosphere. Y

Since the inlet-port 11 is somewhat lower down or extends farther towa rd-the chiselbushing than the ports 12 and 13, it will be seen that when the piston 14 is in its extreme left-hand position the inlet-ports 12 and 13 will be closed, while the port 11 will be only partly open to permit but a small portion of air to enter the port 2l to effect the return of the piston.

35 designates a soft-rubber jacket or grip around the cylinder 2, having the beads 36 and 37 at the ends thereof to prevent the main body of the cylinder from coming in contact with the dust and also to form a shoulder for the hand, said grip being intended to take up the vibration and to insure a firm hold upon the tool, said grip also having the internal bead 38, which is adapted to engage a recess in said cylinder.

The differential diameter pistons which have been heretofore employed in pneumatic tools with which I am familiar all have the disadvantage that the motive fluid acts on the small pressure area all the time, and consequently when the piston is driven forward by the pressure on the larger pressure area it must overcome the pressure on the small pressure area and will therefore lose some of its power. In my invention, however, it will be seen that these difficulties are overcome, since the pressure will exhaust from the small pressure area when the piston has made its extreme backward stroke, and there is consequently no cushion on said piston when it delivers its blow upon the shank 5 of the chisel, whereby an exceedingly powerful, direct, and unimpeded blow is obtained, as is evident.

It will be apparent that various changes may be made by those skilled in the art which will come within the scope of my invention, and I do not, therefore, desire to be limited in every instance to the exact construction herein shown and described.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. In a pneumatic tool, a cylinder, a differential piston therein, a plurality of passages for admitting motive fluid to the exterior surfaces of the dierential areas ot' said piston, and means for permitting the exhaust of the motive fluid from the small pressure area of said piston, when the latter has made its extreme backward stroke, without creating a cushion at the front of said piston when the latter delivers its forward blow to the chisel.

2. In a valveless pneumatic tool, a cylinder, a differential piston therein, means permitting admission of but a small portion of the motive fluid to return said piston, and means for permitting the exhaust of the motive fluid from the small pressure area of said piston, when the latter has made its extreme backward stroke, without creating a cushion on said piston when the latter delivers its forward blow to the chisel.

3. In a valveless pneumatic tool, a cylinder, a differential-diameter piston therein, ports, and passages extending parallel with the length of the piston common to said cylinder and piston, and means for permitting the exhaust of the motive fluid from the small pressure area of said piston, when the latter has made its extreme backward stroke, without creating a cushion on said piston when it delivers its forward blow to the shank of the chisel.

4. In a pneumatic tool, a cylinder, a differential-diameter piston therein, a plurality of inlet-passages for the motive fluid, and ports leading from said passages to the interior of said cylinder at different points, whereby when said piston is in one of its extreme positions, only one of said ports will be partly open, so as to permit the admission of but a small portion of the motive fluid to return said piston.

5. In a pneumatic tool, a cylinder, a differential-diameter piston therein, means for permitting the exhaust of the motive fluid from the small pressure area of said piston, when the latter has made its extreme backward stroke, a plurality of inlet-passages for the motive fluid, and ports leading from said passages to the interior of said cylinder at different points, whereby when said piston is in one of its extreme positions, only one of said admission-ports will be partly open.

6. In a pneumatic tool, a cylinder, a differential piston therein,havin g an enlarged head, provided with differential-pressure areas on opposite portions thereof, a smaller head on said piston, a neck uniting said heads, a third head on said piston, a neck uniting said two last-mentioned heads, whereby a chamber constantly open to live motive fluid is formed, means for conducting motive fluid to said pressure areas from said chamber, and means for exhausting said motive fluid from said pressure areas.

7. In a pneumatic tool, a cylinder, a differential piston therein,having an enlarged head, provided with differential-pressure areason opposite portions thereof, a smaller head on said piston, a neck uniting said heads, a third head on said piston, a neck uniting said two last mentioned heads, whereby a chamber constantly open to live motive fluid is formed, a striker on the forward end of said piston, means for conducting motive fluid to said pressure areas from said chamber, and means for exhausting said motive fluid from said pressure areas.

8. In a pneumatic tool, a cylinder, a differential piston therein, having an enlarged head provided with differential-pressure areas on opposite portions thereof, a smaller head on said piston, a neck joining said heads, a third head on said piston of the same diameter as said smaller head, a neck uniting said last two mentioned heads whereby a chamber constantly open to live motive fluid is formed, and a plurality of ports discharging into said chamber at different points whereby when said piston is in one of its extreme positions only a portion of one port will be open for the admission of motive fluid to return said piston.

9. The combination with the cylinder of a IIC pneumatic tool, of a rubber grip incasing said cylinder, beads on the outer extremities of said grip, and an internal bead on said grip, adapted to engage a contiguous recess in said cylinder.

` 10. A pneumatic tool consisting of a cylin- .der having inlet-passages therein, a dierential piston in said cylinder, a plurality of longitudinal ports 11,A 12 and 13 and ports and passages 2l, 22 and 23 for conveying live motive uid to the smaller area of said piston, ports and passages 28, 29 and 30 for conveying motive iiuid to the larger area of said piston, and means for permitting the exhaust of the motive fluid from the smaller pressure area of said piston, when the latter has made its backward stroke without creating a cushion at the front of said piston when the latter delivers its forward blow to the tool.

11. A pneumatic tool consisting of a cylinder having inlet-passages therein of different lengths extending parallel with the length of the piston to conduct the motive Huid to the smaller pressure areas of the piston, a differential piston in said cylinder, ports and passages 21, 22 and 23 for conveying live motive fluid to the smaller area of said piston, ports and passages 2S, 29 and 30 for conveying motive fluid to the larger area of said piston, and means for permitting the exhaust of the motive Iiuid from the smaller pressure" area of said piston, when the latter has made its backward stroke without creating a cushion at the front of said piston when the latter delivers its forward blow to the tool.

12. In a pneumatic tool, a cylindera dierential piston therein, a plurality of longitudinal passages of different lengths for admitting motive fluid to the differential areas of said piston, means for permitting the exhaust of the motive fluid from the smaller pressure area of said piston, when the latter has made its extreme backward stroke without creating a cushion at the front of said piston when the-latter delivers its forward blow to the chisel, and a head on the forward portion of said piston, adapted to control the iiow of motive fluid to the smaller differential area of said piston.

13. In a pneumatic tool, a cylinder, a dierential piston therein, a plurality of longitudinal passages of dierent lengths for admitting motive fluid to the differential areas of said piston, means for permitting the exhaust of the motive fluid from the smaller pressure area of said piston, when the latter has made its extreme backward stroke without creating a cushion at the front'of said piston'when the latter delivers its forward blow to the chisel, and a head on the forward portion of said piston, adapted to control the flow of Inotive l'luid to the smaller differential area of said piston, in combination with a striker on said last-mentioned head, and a port in advance of the latter leadingto the atmosphere.

HERMAN Gr. KOTTEN. 

